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    <a href="../index.html">cppreference.com</a> &gt; <a href=
    "index.html">Standard C I/O</a> &gt; <a href=
    "fflush.html">fflush</a>
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    fflush
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    Syntax:
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  <pre class="syntax-box">
  #include &lt;stdio.h&gt;
  int fflush( FILE *stream );
</pre>

  <p>If the given file <em>stream</em> is an output stream, then
  fflush() causes the output buffer to be written to the file. If the
  given <em>stream</em> is of the input type, then fflush() causes the
  input buffer to be cleared. fflush() is useful when debugging, if a
  program segfaults before it has a chance to write output to the
  screen. Calling fflush( <strong>stdout</strong> ) directly after
  debugging output will ensure that your output is displayed at the
  correct time.</p>
  <pre class="example-code">
   printf( &quot;Before first call\n&quot; );
   fflush( <strong>stdout</strong> );
   shady_function();
   printf( &quot;Before second call\n&quot; );
   fflush( <strong>stdout</strong> );
   dangerous_dereference();             
</pre>

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